Method of making resilient balls and apparatus therefor.



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iinrran sTaTEs PATENT oEEIoE.

HENRY Z. {10H1} OF 'W'INCHESTER, MASSACHUSETTS, ASSIGNOR TO REVERE RUBBER CDMPANY, A CORPORATION F RHODE ISLAND.

METHOD F MAKING RESILIENT BALLS AND APPARATUS THEREFOR.

i ,a moes.

Application lcd January 10, 1'917.

ot M11 slrhusctis, have invented certain new srtul improvements in Methods of f l\-:.--1lient Balls and Apparatus 11 ahah the following a full,

.tir eximir-.r rrntvs 1o improveniei'lts in moliere mit von! partcrelarly balls for playing mi." wir; games, such as golf and similar i tlm ohjwr et my invention is the rndwiiou '-1' a ball which has the highest invii v :rma-toned with greatest balance. vini f g nini durability. The ball, of ifff r'lnmethod oi making and apparatus reina' fern: the subject matter of this appimntion, is particularly described and china- 2 in my rfc-pending application filed lecombcr lei, i916, Serial No. 136,869.

n detailed dcscriln'ion of one embodi nent' oi my invention, reference may be had i the ioilmvsg specification and to the :1cH imply/ing drawing forming a part there o?, in nai-ch: A

Figure l is a transverse sectional view of mj; impnifvrd ball;

Fig-gj. '.3 is an elevation of the soft elastic renter of the ball which is preferably proi bled with a mctniiic core;

Fig. ."5 is a transverse sei-tional viciv of the mold for forming the latter; and

i* ig. fl is a plan view ot' the equatorial. ring portions ot' the mold segregated from the main portions thereof.

llreily stared, the ball when intended for use in pbiying roltz consists preferablyof a central metallic core 1, such as an accurately geland steel ball of the pro" `r size to give thi f 'emired weight to the '1. About the central core i is molded a body of elastic,

lier rneierial 2 of any suitable composibl vulcanizable rubber. This w "wenn tion is provided with a plurali' i et' #sawing holes or pockets 3 which eintritt into er through the composltlon to ilu metallic core 1. "The central r nf eh fuuposition is then preferrnf ered v.' '1 a thin skin or jacket 4 of rubber in ehe form of a small bag of substr iti lijf 'pure rubber, such as that employed nog to; balloons. Upon the latter is wou the usual rubber thread 5 under high tension, and the Whole is covered with e procent rel Specification of Lettera Patent.

Patented June 18, 1918.

Serial No. 141,557.

tec-tive envelop 6, preferably of plastic material such as balata.

The mold which I 'have devised for forming the layer of molded elastic composition is one of the important features of my invention, and is particilarly adapted for molding vulcanizable.irubber compound although vit is adapted' for molding other compounds in which vulcanization is not necessary. This mold is shown in Figs. 3 and 4. It consists of upper and lower por tions 7 and 8 within which are symmetrically located cavities which are adapted to form the central layer or body in spherical i'orln for a portion thereof, cach side of a central Zone. The halves 7 and 8 of the mold are each provided with tapering pins 9 and l0, which are adapted to come accurately in contact with the metallic ball when in position for molding, as illustrated in Fig. 3. Four other similar pins are provided in the two halves of the mold cavities in the parts 7 and 8, as indicated by 1l and 12. These, preferably, do not extend inward suf` liciently to Contact with the ball l, and being somewhat shorter, form similarly shaped but shallower pockets. The central equatorial zone of the ball is formed by a ring consisting of two parts 13 and 14 which fit in corresponding grooves or recesses in the mold sections 7 and 8. The ring sections are each provided with pins 15 and 16 which are similar to 9 and l0 and are adapted to contact withA the surface of the metallic core when in position. The pins 9, 10, 15 and 1G therefore constitute six supporting or centering points for fixing' the position of the metallic core accurately Within the mold. Contrary to usual opinion, the pins do not, by reason of their convergence, prevent the molded layer from being easily removed from the mold and I have found that the composition is easily freed from the mold aftervulcanization or molding. This is due te the fact that the rubber yvhen vulcanized possesses substantially tht laune elasticresilient characteristics of the ordinary soft rubber. In the present instance to remove the rubber sphere from the mold sections the upper section 7 is raised, thereby simultaneously freeing the vulcanized sphere from both the mold section and attached pins. The lower section 8 may be removed in a similar manner. The sections 13 :11161.14 may then be reino-red by similarly withdrawtoy ing them in a radial direction from the rub ber sphere, the sphere yielding and stretchlng to permit the radially disposed pins to be freed from their engagement wlth the converging openings in the sphere. The mold sections. may be rovided with the usual overliow recesses l if necessary.

When rubber composition is to be vulcanized the mold sections are filled with raw rubber composition and the ball placed in position on the centering pins. The mold is then placed between the steam-heated platens of an hydraulic press and the rubber cured or vulcanized in the usual way. If the composition is one which is merely required to set, the material may be poured into the mold through a suitable opening or openings. 4

What I claim and desire to protect by Letters Patent is:

l. A mold for bodies of elastic material comprising mold sectionshaving symmetrical cavities therein which register with each other, and tapering pins extending radially from the surfaces of said cavities toward a common center.

2. A mold for spherical bodies of elastic material comprising mold sections having semi-spherical cavities therein, and tapering pins extending radially from the surfaces of said cavities towardf'the center.

3. A mold for spherical bodies of elastic material comprisin mold sections having Semispherieal cavities therein, tapering pins extending radially from the surfaces of said cavities toward the center thereof, equatorial ring sections adapted to be seated in recesses in said mold sections, and pins extending from said ring sections toward said center.

4. A method of molding elastic bodies having conver ing openings, comprising placing moldab e material in a mold having tapering radial pins converging toward a common center, and symmetrically located at substantially equal distances apart throughout the entire mold cavity, allowing said material to harden or set, and then withdrawing said material over said pins.

5. A method of making elastic bodies having conver ing openings, comprisin locating a har spherical ball accuratelg upon a series of radial pinssymlnetrically ocated at substantially equal distances throughout the entire mold cavity, surrounding said 'ball with moldable material, allowing said material to harden or set, and then removing the molded body by withdrawing the same over said pins.

6. A method of molding spherical bodies of elastic material having converging openings therein, comprising llocating a hard spherical ball accurately upon a series of radial tapering pins within a sectional mold and extending inward from six symmetrical points, surrounding said ball with moldable material, allowing said material to harden or set, and then removing the molded body by withdrawing (he same over said ins.

7. A mold for spherical bodies o elastic material comprising mold sections having pins extending from the mold walls into the mold cavity symmetrically located at substantiall'y equal distances throughout the entire cavlty.

8. A mold for spherical bodies of elastic material comprising mold sections forming collectively a spherical cavity, and pins extending' into said cavity from the wall of the sections and symmetrically located at substantially equal distances throughout the cavity and terminating at equal distances from the center of the cavity.

9. A mold for spherical bodies of elastic material comprising mold sections forming collectively a sphcricai cavity, and sets of pins extending into said cavity from the walls of the sections, one set of said pins being symmetrically located and equally spaced and terminating at equal distances from the center of the cavity, and another set of said pins being symmetrically located and equally spaced and terminating at equal distances from the center of the cavity but at a greater distance than the first, set.

10. A method of molding elastic bodies having convergin openings, which consists` in placing molde le material in a sectional mold having radial pins converging from the respective mold sections toward a comeA mon center, allowing said materialr to set into a yieldablc mass, and then withdrawing said material from the respective mold sections and their converging pins simultaneously.

11. A method of molding elastic bodies having conver ing openings, comprisin placin moldab e material in a sectiona mold aving a plurality of radial pins converging from the wall of each section toward a common center, 'allowing said material to set into a yieldable mass, and then withdrawing sald material simultaneousl over said converging pins and from the mo d section to which they are secured.

Signed at Provldence, R. I., this 4 day of January, 1917.

HENRY Z. COBB. 

